<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>
<body>
<script>
  class Father {
    constructor() {
    }
    money() {
      console.log(100);
    }
  }

  class Son extends Father {

  }
  var son = new Son();
  son.money()  // => 100
</script>
</body>
</html>